Table Of ContentWater-from-Air
Quick Guide
Second Edition
Roland V. Wahlgren
Atmoswater Research
Cover image: A thermoelectric device provided a chilled surface with temperature below the dew-point for
condensation of water from the air.
© 2016–2018 by Roland V. Wahlgren, Atmoswater Research. All rights reserved
No part of this book may be reproduced in any form
or by any means without permission in writing from the publisher.
First edition March 2016
Second edition June 2016
Reprinted September 2016 (with minor corrections)
Reprinted July 2017 (with minor corrections)
Reprinted July 2018 (with minor corrections)
Published by
Atmoswater Research
2116 Grand Boulevard
North Vancouver, BC, V7L 3Y7
Canada
www.atmoswater.com
ISBN: 1523638818
ISBN-13: 978-1523638819
To the advancement of the water-from-air industry
The author compiled the information in this Quick Guide. It is reviewed and updated periodically. Comments,
criticisms, and suggestions regarding the subject matter for future printings or editions are invited. Any errors
or omissions in the contents should be brought to the attention of the author. In no way is the use of trade
names intended to imply approval of any particular source or brand name over other similar ones not
mentioned in the book. Product, company, or trade names should be presumed to be trademarks or service
marks of their respective companies. Tables, figures, and photographs are by the author unless otherwise
noted. The second edition incorporated a revised Case Studies section, a revised Appendix 5: Normalizing Water
Production Rates, some revised illustrations and captions, plus some minor typographic corrections (September
2016 and July 2017). In response to a reader’s comments, the July 2018 reprinted second edition incorporated
revised tables in Chapter 4 with wider temperature ranges for water vapour density, humidity ratio, and dew-
point. The July 2018 reprinted edition had also a revised Appendix 6: Economics of Off-grid Solar PV For WFA
and additional minor corrections.
DISCLAIMER OF WARRANTY
The author and publisher have used their best efforts in the preparation of this book. Atmoswater Research
and the author make no representation or warranties as to the accuracy or completeness of the book’s
contents. It is sold as-is, without warranty of any kind, either express or implied, including but not limited to
implied warranties for the book’s quality, merchantability, or fitness for any particular purpose. Neither the
author or publisher nor distributors or dealers of the book shall be liable to any person, purchaser, or user
concerning any loss of profit or any other damage, including but not limited to special, incidental,
consequential, or other damages directly or indirectly related to the book or its contents.
CONTENTS
PURPOSE ........................................................................................................................... VII
1. WATER-FROM-AIR ........................................................................................................ 1
Historical Perspective ................................................................................................. 1
Applications .................................................................................................................... 2
Dehumidifiers with a Difference ............................................................................ 4
2. WATER VAPOUR IS A WATER RESOURCE .......................................................... 5
3. WHERE ARE WATER-FROM-AIR SYSTEMS PRACTICAL? .............................. 7
Practicality in Relation to Cities with Water Scarcity .................................... 9
Effect of Climate Change on the Water-from-Air Resource ....................... 10
Effect of Droughts on the Water-from-Air Resource .................................... 13
4. TWO PROPERTIES OF THE AIR TO KNOW ...................................................... 19
Water Vapour Density .............................................................................................. 19
Dew-point ....................................................................................................................... 24
5. WATER-FROM-AIR MACHINES .............................................................................. 27
Processors of Atmospheric Water Vapour ....................................................... 27
Properties of Liquid Water Near Its Freezing Point ..................................... 32
Water-from-Air Machine Schematic View ........................................................ 33
Advantages of Water-from-Air .............................................................................. 34
Water-from-Air Niches ............................................................................................. 34
Computer Simulations .............................................................................................. 35
Limits to Mechanical Dehumidification Efficiency ........................................ 36
System Sizes and Markets ....................................................................................... 38
Water Phase Change Methods ............................................................................... 39
Energy Cost of Water ................................................................................................. 39
Water-from-Air Power Sources ............................................................................ 40
Water Treatment Methods ...................................................................................... 41
Case Studies ................................................................................................................... 42
Amortization of Water Cost .................................................................................... 43
Water-from-Air Equipment Supplier Checklist for Credibility ................ 44
6. THE FUTURE OF WATER-FROM-AIR TECHNOLOGIES .............................. 45
v
Contents
WATER-FROM-AIR READING LIST .......................................................................... 47
REFERENCES .................................................................................................................... 49
APPENDIX 1: ENVIRONMENTAL IMPACT ............................................................ 51
Environmental Impact on the Atmospheric Water Reservoir ................. 51
Precipitation Enhancement .................................................................................... 52
Indirect Environmental Impacts .......................................................................... 52
Conclusion ..................................................................................................................... 52
References for Appendix 1 ...................................................................................... 53
APPENDIX 2: GUIDE TO THE WATER-FROM-AIR RESOURCE CHART ..... 55
APPENDIX 3: DEW-POINT AND WATER VAPOUR DENSITY AGAINST
SITE ELEVATION ABOVE SEA LEVEL ................................................................... 57
APPENDIX 4: HOURLY ANALYSIS OF THE WFA RESOURCE ........................ 61
APPENDIX 5: NORMALIZING WATER PRODUCTION RATES ...................... 67
METHOD ............................................................................................................................. 68
Revisions to Dehumidifier Standard Test Conditions ................................. 69
Appropriateness of Non-standard Test Conditions ...................................... 71
Normalizing Examples .............................................................................................. 72
APPENDIX 6: ECONOMICS OF OFF-GRID SOLAR PV FOR WFA .................. 73
Example 1: PV Power Supply for an AWG, Input Power 1.05 kW ............ 73
Example 2: PV Power Supply for an AWG, Input Power 2.1 kW .............. 76
Solar PV Power Supplies for Examples 1 and 2 .............................................. 79
Price Ratios for Off-grid Solar PV Systems Applied to Two AWGs .......... 81
APPENDIX 7: DRINKING-WATER QUALITY GUIDELINES ........................... 83
Water Quality—Microbiological ........................................................................... 83
Water Quality—Physical and Chemical ............................................................. 84
APPENDIX 8: ATLAS OF THE WATER VAPOUR DENSITY FIELD AT
EARTH’S SURFACE BY MONTH ................................................................................. 87
APPENDIX 9: WATER-FROM-AIR RESOURCE CHARTS FOR 23 CITIES
WITH WATER SCARCITY ............................................................................................ 101
GLOSSARY ........................................................................................................................ 127
INDEX ................................................................................................................................ 129
vi
PURPOSE
Technical and scientific aspects of water-from-air machine (atmospheric water generator) operation are
introduced and explained for prospective buyers, owners, and users of this equipment. The knowledge in this
guide is valuable for making cost-effective decisions about using the freshwater resource that exists in Earth’s
atmosphere.
vii
1. WATER-FROM-AIR
H
uman population growth and climate change are causing droughts—regional scarcity of liquid water
sources for supporting human, animal, and plant populations. Conventional water supplies from
surface water and groundwater cannot meet demands for fresh water. Water conservation and
improvements in distribution efficiency are worthwhile but are often inadequate to ensure enough water for
people, commerce, and industry. The innovative water supply solution most often turned to, desalination, has
significant bad impacts on our ecosystems because large quantities of waste brine are created.
Water-from-air technologies cannot compete on an energy cost of water basis with ample sources of
liquid water, although polluted or contaminated, that can be treated by standard filtration and chemical
methods. This is explained in Chapter 2, “Water Vapour is a Water Resource”. But, even so, there are many
applications where water-from-air can be the ideal choice.
Historical Perspective
Potable water is not always available from surface
water, groundwater, or rainwater harvesting when
and where needed. Many people, throughout history,
have been fascinated with the concept of gathering
dew to augment scarce water resources.
Water-from-air (WFA) technology in its present
form started with US Patent 661,944 issued to E. S.
Belden in 1900 for his apparatus for removing
moisture from air (see Figure 1).
Alexander Graham Bell, known for
commercializing the telephone, was interested in
providing emergency water rations to shipwrecked
sailors marooned in lifeboats. Bell experimented with
water-from-air devices in the early 1900s (Eber, 1991,
p. 77–78, 82).
Mitsubishi Electric Corporation (Japan) was
active in the industry already in 1981 with its
Japanese Patent 56-56216 for a two column
atmospheric water condensation apparatus.
Smaller companies, entirely devoted to the WFA
industry began forming in the 1990s. Some of these
Figure 1. Sheet 1 of US Patent 661,944, issued to E. S.
continue to the present.
Belden in 1900 for an Apparatus for Removing Moisture
The water scarcity crisis continues to deepen with
from Air. Source: United States Patent and Trademark
water scarcity now affecting four billion people
Office (public domain).
(Mekonnen & Hoekstra, 2016).
1
Atmoswater Research
Applications
Water-from-air machines have already been used in several roles
• emergency water supplies after natural disasters (USA,
Haiti);
• military troop water supplies produced at site of need—
reducing reliance on vulnerable supply lines;
• alternative to municipal tap water with perceived quality
problems—households and businesses interested in
water supply quality, independence, and security; and
• alternative to bottled water machines in homes and
offices and associated vending machines (see Figure
2)—no need to transport and lift heavy 5-gallon (20 L)
bottles—also avoids the environmental burden of
bottled water.
Figure 2. Water vending machine in Grand Turk,
Specific projects, listed by country, include Turks and Caicos Islands (2002).
• Australia: Case study by World Environmental Solutions Pty Ltd;
• Gabon: Project by Water World Solution;
• Honduras: Water-Gen, atmospheric water generators;
• India, Chennai: MARG Properties Savithanjali development;
• India, Gujarat, Ahmedabad, Bopal: SUSTECH CENTER, Sun City (Dew Harvesting);
• India: Jalimudi Village Project (WaterMaker India);
• India: Various locations by WaterMaker India;
• Nigeria: Nerios Water Making System in Liberation City in Lagos;
• Panama: Gold mine;
• Qatar: Farm irrigation;
• Slovakia: Water-Gen, atmospheric water generators;
• UAE, Abu Dhabi: Gas facility;
• UAE, Abu Dhabi: UAE Water—Skywater atmospheric water case studies;
• UAE, Sharjah: Sharjah English School;
• USA, California, Irvine: Urban Produce;
• USA, California, Los Angeles: Dodger Stadium;
• USA, Hawaii: NELHA Gateway Project;
• USA, Texas, Dripping Springs: Nerios Water Making System at Mazama Coffee;
• USA, Texas, Houston: Applied Cryo Technologies; and
• USA: Office Depot.
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